A video of the fatal shooting of a Taiwanese fishing vessel allegedly shows six Filipino coast guards laughing as they fired at the boat, according to a source, who said the incident was "embarrassing" for the Philippines.

"The video showed the soldiers acted unprofessionally. They were laughing while they were shooting the boat," a source, who saw a video of the Philippine Coast Guard shooting at fishing boat Guang Ta Hsin 28 three weeks ago, said on Saturday.

"It is disturbing and embarrassing for Philippine law enforcers," the source, who spoke on condition of anonymity, told the Inquirer in an interview.

Taiwanese fisherman Hung Shih-chen, 65, was hit and killed in the shooting, which happened during a high-speed chase in waters off Balintang Island in the northern Philippines on May 9.

The source said the Coast Guard submitted the video to the National Bureau of Investigation (NBI) after President Benigno Aquino III ordered an investigation of the fatal shooting of Hung, which sparked a major diplomatic row between Taiwan and the Philippines.

Justice Secretary Leila de Lima described the video two weeks ago as "very revealing", but did not disclose its content.

But because it was so revealing was probably why the Department of Justice initially refused to share the video with Taiwanese investigators, delaying clearance from Taipei for an NBI team to travel to Taiwan to investigate the fatal shooting of Hung.

Not until De Lima allowed the video to be seen by Taiwanese investigators did the Taipei Economic and Cultural Office (Teco), Taiwan's de facto embassy in Manila, give visas to the eight members of the NBI team.

The source said the video showed the fishing boat, after sailing side by side with the MCS-3001, a patrol vessel owned by the Bureau of Fisheries and Aquatic Resources but manned by coast guards, peeled away and moved in "circles, as if daring the (coast guard vessel) to come after it".

Not raked with gunfire

Contrary to reports, the source said, the coast guards did not rake the fishing boat with gunfire.

"They did not spray it with bullets, but they were laughing as they fired at the fishing boat," the source said.

The coast guards aimed for what they thought was the engine room to stop the boat, the source said.

But the NBI inspection of the fishing boat at the dockyard on Pingtung Island, southern Taiwan, showed no bullet holes on any part of the engine room.

"There were no bullet holes on the engine room probably because (the coast guards) did not know its location," the source said.

Two other sources who had seen the video confirmed the statements of the first source.

According to the Coast Guard report on the incident, Cmdr Arnold de la Cruz, the patrol vessel's commander, "ordered his men to fire at the fishing vessel when it did not stop after several warnings".

Philippine waters

One of the two other sources who had seen the video said the shooting happened on the Philippine side, not on the Taiwan side, of overlapping territorial waters between the two countries.

The NBI and Taiwanese investigators ended their parallel probes of the incident on Friday, with the NBI team saying its report would be ready in a "day or two".

De Lima said the government's next step would depend on the NBI report, which would contain recommendations.

She said Philippine laws would be followed should the NBI recommend the prosecution of the coast guards involved in the shooting.